1. Field of the Invention
This invention relates to a burn-in apparatus, and, in particular, to a burn-in apparatus in which semiconductor devices are held on burn-in boards for electrical connection not by means of sockets but through air suction.
2. Description of the Related Art
When semiconductor devices have been assembled, they are left to stand under severe conditions of high temperature and high voltage, usually for 10 to 40 hours, with a view to revealing any defects that would have caused an early failure. Subsequently, the semiconductor devices are subjected to a burn-in test, i.e., an accelerated test, in which their quality is judged by examining them for certain electrical properties, etc. Being conducted under severe conditions, the burn-in test simulates operating the semiconductor devices for a long period, for example, for several months, under real use conditions. Thus, any defects of the semiconductor devices that would have caused an early failure can be revealed through this test. Since this test takes a long time, a large number of semiconductor devices are subjected to it at one time.
FIG. 1 is a perspective view showing the outward appearance of a conventional burn-in apparatus. (Since an embodiment of the present invention has the same outward appearance as this one, FIG. 1 will also be referred to when describing the present invention.) FIG. 2 is a perspective view of a zone frame provided in the burn-in apparatus shown in FIG. 1, and FIG. 3 is a front view of this zone frame. The inner space of the burn-in apparatus, 1, which is opened by a door 1a, is divided into two sections by a side plate 2a. One of these sections is formed as a chamber 2. Provided on the side plate 2a are a heater, a blower, and so on (not shown) which keep the temperature in the chamber 2 constant. Basically, the same air pressure and the same atmosphere (air) are maintained in the chamber 2 as in the exterior. Arranged in the chamber 2 is a zone frame 3 on which board guides 4 are mounted. These board guides 4 support burn-in boards to which semiconductor devices to be subjected to a burn-in test are attached. Provided on the back wall of the chamber 2 are connectors 5 which are electrically connected to the semiconductor devices attached to the burn-in boards. One connector 5 is provided for each pair of board guides 4.
FIG. 4 is a plan view of a conventional burn-in board, and FIG. 5 is a perspective view of a socket to be attached to this burn-in board.
A burn-in board 7 shown is to be set in the above-described conventional burn-in apparatus 1. Attached to the main surface 8 of the burn-in board 7 are a multitude of sockets 6, into which semiconductor devices (not shown) are inserted and in which they are fixed. When the burn-in board 7, thus equipped with semiconductor devices, has been inserted through the board guides 4, the burn-in apparatus 1 transmits an electrical signal through the associated connector 5 to the semiconductor devices. In this condition, the inner space of the chamber 2 is set to a desired temperature. Thus, the burn-in test is conducted under conditions of high temperature and high voltage.
The problem with the burn-in apparatus 1 described above is that it requires a lot of sockets 6, as shown in FIG. 4. The cost of these sockets is rather high compared with the cost of the burn-in board 7.
In addition, the leads of semiconductor devices may be bent when inserting them into or extracting them from the sockets 6.